Pipe joint and method of assembly

ABSTRACT

A pipe joint specifically adapted for an oil lamp inlet screen, and a method of assembly therefor, comprising a metal pipe adapted at one end to be connected to an oil pump housing and a filter screen including a molded plastic screen housing having an aperture adapted to receive the other pipe end. A metal eyelet is molded into the plastic housing and extends therefrom to embrace a circumferential rib formed on the outside surface of the pipe. An annular resilient sealing ring surrounds the pipe and is captured by the eyelet in sealing compression between the circumferential rib and the housing.

This is a division of application Ser. No. 882,269, filed Feb. 28, 1978now U.S. Pat. No. 4,129,503, issued Dec. 12, 1978.

The present invention relates to metal-to-plastic pipe or tube jointsand to methods for manufacture thereof. More particularly, the inventionrelates to joints between the pipe and housing of an oil pump inletscreen assembly for an internal combustion engine or the like.

An object of the present invention is to provide an economical andreliable metal-to-plastic pipe joint and a method for manufacturethereof. More specific objects of the invention are to provide a jointbetween a metal pipe and plastic housing adapted for use in an oil pumpinlet screen assembly which is able to withstand the high temperatureand vibration conditions of an internal combustion engine oilcirculation system. A particular object of the invention is to provide ametal-to-plastic pipe joint for use in the environment described whichprevents plastic shrinkage and/or creep in the zone of the pipe jointand consequent loss of sealing engagement between the joint members.

The accompanying drawings may be briefly described as follows:

FIG. 1 is a broken elevational view of an oil pump inlet screen assemblyin accordance with the invention;

FIG. 2 is an enlarged view of the pipe joint illustrated in FIG. 1; and

FIG. 3 is an exploded perspective view illustrating assembly of the pipejoint in FIG. 2.

Referring to FIG. 1, an oil pump inlet screen assembly 10 in accordancewith the invention comprises a metal conduit or pipe 12 having one end14 adapted to be connected to an oil pump housing (not shown), and afilter screen generally indicated at 16 connected to a second pipe end18 such that screen 16 may be suspended by pipe 12 from the pump housingand immersed in an oil sump. Screen 16 includes a downwardly dishedhousing 17 having a galvanized wire mesh 19 ultrasonically staked orwelded around the downwardly opening edge 20 thereof. A pressure-reliefflapper or leaf valve 22 is disposed in mesh 19 to provide unfilteredoil to the pump should mesh 19 become clogged, and comprises a collar 24crimped around an opening in mesh 19 and capturing a leaf valve element26 therein. Valves of the type illustrated at 22 are generally wellknown in the art and need not be described further.

Turning now to FIG. 2 in conjunction with FIG. 1, a presently preferredembodiment of the joint between metal pipe 12 and molded plastic housing17 is indicated generally at 28. A metal eyelet 30 is molded into anupstanding shoulder portion 32 of housing 17 and includes at its innerend an outwardly-directed flange 34 disposed within shoulder portion 32to resist removal of eyelet 30 from the housing. A generally cylindricalend 36 of pipe 12 is received in an aperture 38 in shoulder portion 32of housing 17. Pipe end 36 includes a circumferential rib 40 formed onthe outside surface of the pipe and embraced in assembly by the inwardlycrimped outer end 42 of eyelet 30. An annular resilient sealing O-ring44 is captured in compression by eyelet 30 between rib 40 and housingshoulder 32 to form an air-tight seal between the pipe and housing jointelements.

In accordance with an important feature of the invention, the inner edge46 of pipe end 36 is flared radially outwardly within housing 17 andthereby places the zone or portion of housing shoulder portion 32 in theregion of the pipe joint in a state of residual compression. Thisresidual compressive stress condition, combined with the rigidifyingeffect of eyelet 30 molded into the housing, resists expansion and creepof the plastic material in the region of the joint under the severetemperature and high vibration environment of an internal combustionengine oil circulation system. Thus, the screen assembly and pipe jointprovided by the invention combines the cost advantages of aninjection-molded housing 17 with the strength and rigidity of a metaltube 12 by means of which the housing 17 is suspended from an oil pump.

FIG. 3 illustrated the pipe joint elements prior to assembly. As notedabove, eyelet 30 is molded into plastic housing 17. Sealing ring 44 isplaced over end 36 of pipe 12 against rib 40. Pipe end 36 is theninserted into housing aperture 38 such that sealing ring 44 is incompression, and then inner pipe edge 46 is flared radially outwardlyagainst the opposing portion of housing 17 as hereinabove described. Theouter end 42 of eyelet 30 is then rolled or crimped over pipe rib 40 tocapture sealing ring 44 in compression against pipe end 36 and housingshoulder 32 to form an air-tight seal.

I claim:
 1. A pipe joint comprising a first member of molded plasticmaterial having an aperture, a pipe having an end received into saidaperture and a circumferential rib formed on an outer surface spacedfrom said first member, annular resilient sealing means disposed betweensaid rib and said first member surrounding said pipe end, and a metaleyelet having one end molded into said first member and a second endrolled over said rib to capture said resilient sealing means incompression between said rib and said first member.
 2. The pipe jointset forth in 1 wherein said one end of said pipe is flared radiallyoutwardly within said first member, said member being in residualcompression in a zone surrounding said joint.
 3. A method of forming anair-tight metal-to-plastic pipe joint comprising the steps of: (a)forming a molded plastic member having a generally cylindrical apertureand a metal eyelet having a first end molded therein and a second endextending from said member surrounding said aperture, (b) providing ametal pipe having a substantially cylindrical pipe end and acircumferential rib formed on an outer surface of said pipe spaced fromsaid pipe end, (c) placing an annular resilient sealing ring over saidpipe end, (d) inserting said pipe end into said aperture, and (e)forming said second end of said eyelet over said rib to compress saidsealing ring between said rib and said plastic member.
 4. The method setforth in 3 comprising the additional step of (f) placing said member inresidual compression in a zone surrounding said joint by flaring saidend of said pipe radially outwardly against an opposing portion of saidmember.